Printer with print bars supported by parallelogram linkage arrangement



3,444,975 OGRAM May 20, 1969- E. D. SIMSHAUSER PRINTER WITH PRINT BARS SUPPORTED BY PARALLEL LINKAGE ARRANGEMENT Sheet Filed March 20, 1963 "15: @i WW NVEIQTOR firm/4D. .si wm wiz Irma/y May 20, 1969 E. D. SIMSHAUSER PRINTER WITH PRINT BARS SUPPORTED BY PARALLELOGRAM LINKAGE ARRANGEMENT Sheet 3 Filed March 20. 1963 l N VE N TOR. fi m Q Jinrwwrt United States Patent PRINTER WITH PRINT BARS SUPPORTED BY PARALLELOGRAM LINKAGE ARRANGEMENT Elvin Dean Simshauser, Merchantville, N.J., assignor to Radio Corporation of America, a corporation of Delaware Filed Mar. 20, 1963, Ser. No. 266,679 Int. Cl. B411 /00 US. Cl. 197-1 6 Claims The present invention relates to information translating apparatus, and particularly to apparatus for printing on a document.

The invention is especially useful in high speed printers which print characters successively along a line on a document, the characters being formed from columns of dots. Such printers are called matrix printers. These printers may be controlled by coded electrical signals which represent the characters to be printed. Such signals may, for example, be derived from electronic data processing equipment or from digital communications equipment.

Since electronic data processing or communications equipment usually supplies coded characters at very high speed, a printer suitable for use with such equipment should also operate at high speed. The format of the document printed by the printer desirably should not deviate substantially from the format generally used in business practice. Accordingly, it is desirable for a. printer to print on a line-by-line basis and to provide page-length documents, which are of the type generally used in business. High speed page printers for data processing equipment which meet the foregoing requirements and which are presently available are usually complex, expensive and require a large amount of space. It is further desirable that the printer provide multiple copies of each document. Printing apparatus known in the art usually increases in cost and complexity in relation to the number of copies such as printer can make.

Printers which form characters by printing a plurality of columns of dots sometimes produce unevenly shaded characters when the impact pressure against the paper varies from column to column or from dot to clot. Distorted characters may be produced if dilferent columns are awry or if dots ar smudged. The printing of unevenly shaded characters may result from the application of insufiicient actuating forces to the elements which impact the document to print the characters. Distorted characters may also result from flexural or twisting movements of the printing elements away from their normal path of movement during printing. It is particularly difficult to provide electromagnetic actuating means for the printing elements which develop sutficiently large printing forces. An electromagnetic actuator for developing large printing forces may also be large and difficult to locate in cooperating relationship with the printing elements of a matrix printer without resorting to complex linkages which may impart fiexural or twisting movement to the printing elements during printing.

It is an object of the present invention to provide improved printing apparatus, which may be of the matrix type, wherein the foregoing difficulties and disadvantages may be substantially eliminated.

It is a further object of the present invention to provide improved printing apparatus controllable by character representing code signals and capable of printing characters at high speeds, which printing apparatus may be suitable for use with electronic data processing and communications equipment.

It is a still further object of the present invention to provide improved printing apparatus capable of printing a line by line message format on a page-length document.

3,444,975 Patented May 20, 1969 It is a still further object of the present invention to provide improved printing apparatus capable of making multiple copies of a document at low cost.

It is a still further object of the present invention to provide an improved printer which is low in cost and compact in size.

Briefly desired, printing apparatus embodying the present invention may include a plurality of print bars disposed in side-by-side relationship and adapted to extend across the width of a document. A plurality of laterally extending legs are attached to the print bar and may be integral therewith. The legs may be flexible. Alternatively, the legs may be hinged to the print bar. The legs are attached to a fixed support structure. Each print bar, its legs and the support structure therefor define a parallelogram. Forces which move the print bars longitudinally may be applied thereto, as for example, by electromagnetic actuators which act either directly or indirectly on the print bars. When a print bar is actuated, it moves longitudinally. This longitudinal movement is translated into a lateral movement towards a document for printing thereon by flexing and/ or pivotal movement of the legs which extend from the actuated print bar.

The invention itself, both as to its organization and method of operation, as well as additional objects and advantages thereof, will become more readily apparent from a reading of the following description in connection with the accompanying drawings, in which:

FIG. 1 is a diagrammatic, perspective view of one form of printing apparatus embodying the invention;

FIG. 2 is a fragmentary, elevational view of the printing head used in the apparatus shown in FIG. 1;

FIG. 3 is an enlarged, sectional view taken along the line 3-3 of FIG. 2 as viewed in the direction of the appended arrows;

FIG. 4 is a fragmentary, elevational view of a portion of a print head similar to the head illustrated in FIG. 2, but differing therefrom in some respects;

FIG. 5 is a fragmentary, bottom view of a print head such as shown in FIGS. 2 and 3, illustrating an actuator mechanism for such a print head;

FIG. 6 is a simplified, bottom view of a print head such as shown in FIGS. 2 and 3, illustrating another actuator mechanism for such a print head;

FIG. 7 is a diagrammatic, bottom view illustrating an arrangement of a plurality of actuating mechanisms such as shown in FIG. 6 in a print head such as shown in FIGS. 2 and 3; and,

FIG. 8 is a fragmentary, somewhat schematic, elevational view of a print head in accordance with a further embodiment of the invention.

Referring more particularly to FIG. 1, documents 10 are shown as they travel along a path through the printing apparatus. These documents may be a plurality of interleaved sheets of carbon paper and blank document paper. The carbon paper may overlie the document paper, as viewed in FIG. 1, so that the printed message may be viewed from the top at the output end of the machine, when the carbon paper is stripped away from the blank document paper. Only one sheet of carbon paper backed, blank document paper need be used if a single copy is desired. The use of a plurality of interleaved sheets conveniently provides a plurality of simultaneously printed copies.

The documents 10 may have sprocket holes along one or both edges, sprocket holes 12 along one edge being illustrated for the sake of simplicity. Suitable fixtures for guiding the documents may also be provided. These fixtures may be of the type used for guiding other webs which are normally used with sprocket feeds, as for example, magnetic tapes and motion picture films. The documents may be unwound from a reel and transported through the printer by means of a sprocket 14. The sprocket may be driven by a constant speed electric motor 16, either directly or through an intermittent feed mechanism.

A stanchion 18 supports a document backing member such as an arbor 20 which has a flat, upper surface 22 adjacent the path of the documents extending across the width of the documents 10. This surface 22 may be longer than the width of the documents and wider than the height of the characters which may be printed thereon. An endless belt 24 having a flat outer surface and a corrugated inner surface is trained around the arbor 20. A positive, non-slip drive for this belt includes a capstan 26 having a ribbed surface. The capstan is driven by a constant speed electric motor 28. Alternatively, the capstan 26 may be driven through suitable gearing by the sprocket drive motor 16. In the latter case, the printing of successive lines of characters may be synchronized with the movement of the documents.

A wedge-shaped anvil element 30 is secured to the outer surface of the belt 24 and is driven by the belt across the width of the documents. More than one anvil element 30 may be secured to the belt, if desired, thereby permitting the belt 24 to be driven at reduced speed.

A print head 32 is disposed adjacent the path of the documents 10 on the opposite side of the documents from the backing member 20. This print head 32 is supported by a stanchion 34. The head 32 has a plurality of printing members 35, each including a print bar 36. By way of illustration, five printing members 35 are shown disposed in side-by-side relationship. Each printing member 35 has a plurality of legs 40 which extend laterally and angularly from its print bar 36, and which legs are secured to a fixed support 42. An actuator for the bars 36 is disposed in an enclosure 44 attached to the fixed support 42. Another stanchion (not shown) on the opposite side of the document from the stanchion 34 may be used to more securely support the print bar support 42. The bars 36 extend longitudinally (i.e., in their lengthwise direction) width-wise across the documents 10. The print bars 36 present parallel, longitudinal edges 38 to the documents. These longitudinal edges 38 are opposite to the arbor and the anvil element is perpendicular to these longitudinal edges 38.

When the anvil element 30 travels along the upper surface 22 of the arbor 20, this element 30 moves along a path parallel to the longitudinal edges 38 of the print bar 36. Accordingly, when the bars 36 impact the documents 10 and press the documents against the anvil element 30, a column of dots may be printed, one dot by each of the bars 36. While five printing members are shown, it may be desirable to use more or less such members, depending upon the resolution required. A character may be formed by actuating the print bars 36 successively as the anvil element travels at constant speed from right to left, as viewed in the drawing, across the documents 10. A character may be defined by a predetermined number (for example, five) columns of dots. A line of characters is printed on each traversing of the anvil element across the width of the documents.

For example, the letter B may be formed as the anvil element 30 moves one character space along a line across the document. When the anvil element 30 is at the beginning of the character space, all five printing members 35 are actuated. All five print bars 36 then press the documents against the anvil so as to print a vertical column of five dots forming the vertical leg of the E. After the anvil element moves a short distance to the right, as viewed in FIG. 1, the upper, middle and lower ones of the bars are actuated to print a vertical column of three dots which begin to form the upper, middle and lower horizontal arms of the E. The upper, middle and lower bars 36 are successively actuated three more times. The anvil element 30 moves short distances to the right after each of these three actuations. Three successive columns of three dots are printed and the arms of the E are completely formed. Successive characters are similarly formed by actuated different combinations of print bars to print columns of different combinations of dots. A line of characters is printed across the document for each longitudinal traverse of the print head 32 by the anvil element 30.

The anvil element 30 is transported by the belt 24 across the documents 10 at constant speed in the time required :for the printing of a line. Two or more anvil elements may be used so that when one anvil element leaves one end of the print head after the end of a line, the next anvil element reaches the opposite end of the print head to start the next line. The drive motor 28 for the belt 24 may be synchronized by the data supplied to the actuators 44 or by clock pulses accompanying the data by techniques known in the computer art.

The print head 32 is shown in greater detail in FIGS. 2 and 3. The printing members 35 are relatively thin (15 mils in thickness) and may be made of flexible, resilient material. A metal such as nickel steel is especially suitable due to its abrasion resistance as well as its flexibility and resilience. The legs 40 and the bar 36 of each printing member 35 are integral with each other and may be formed from a sheet of metal, as by stamping. The legs 40 and bars 36 may have the same thickness. The legs are inclined with respect to the bars so as to include an acute angle (for example, approximately 45). As shown in FIG. 3, the legs and bars are disposed in side-by-side, stacked relationship and separated by spacers 46 of nonadhering material, such as a plastic. Teflon sheets may be suitable for the spacers 46. The spacers may be of the same shape as the members 35 between which they are interposed, or they may be generally unbroken or continuous sheets.

Clamping bars 48 are disposed in opposed relation against the outer surfaces of the legs 40 of the outermost printing members. The clamping bars 48 are adjacent the upper or free ends of the legs 40 of the outermost printing members 35 and are parallel to the print bars 36. Bolts 50 through both clamping bars 48 and nuts hold the stack of printing members 35, spacers 46 and legs 40 in assembled relationship. The clamping bars 48, the legs 40 and the print bars 36 form parallelograms. The clamping bars 48 may be housed in the support 42 (FIG. 1) and held therein in fixed position.

Actuators 52 are connected respectively to each of the print bars 36 at one end of each bar. The electromagnetic actuators 52 are shown in FIG. 5. This actuator includes a plurality of solenoids 54, one for each of the five bars 36. The center one of the bars 36 may be connected directly to the armature of its associated solenoid 54. The other bars 36 may have offset connecting members 56 which connect these bars to their associated solenoids 54.

When a selected print bar 36 is actuated, a longitudinal force (a pull toward the right as indicated by the arrow in FIG. 2) is applied thereto. That force is transmitted to the print bars flexible legs 40. These legs then flex at their points of interconnection with the bar 36. The legs also flex at points fixed by the clamp bars 48. The legs and bar move as parts of a parallelogram linkage. The bar 36 moves, laterally downward, without flexing or twisting, as viewed in FIG. 2, as well as longitudinally. The longitudinal edge 38 of the bar 36 assumes a final, downward position, as shown by the dashed lines in FIG. 2, parallel to its initial position. In its final, downward position, the longitudinal edge 38 of the print bar 36 impacts the documents 10 against the edge of the anvil element 30 (FIG. 1). A clear, sharp dot is formed on the blank paper since the carbon paper is pressed against the blank paper by the edge 38 of the print bar 36. Print bars 36 need move only a short distance (for example, 0.002 inch) between initial and final printing position. Such short movements may be executed very quickly; thus, high speed printing is accomplished.

The current applied to the actuator solenoids 54 may be pulses in accordance with a code which represents characters to be printed. When the pulse terminates, the print bars and their associated legs are returned to their initial position by the elastic forces built up therein during actuation. The print bars do not bounce after impact with the document, since impact forces are substantially absorbed by the document. Sharp, clear dots are formed, because the actuator solenoid 54 or other actuating mechanism to be described hereinafter may be sutficiently large to develop uniformly high printing forces which are applied to the print bars 36. Distorted letters due to awry columns of dots are also substantially eliminated since the bars do not flex or twist during impact with the documents, since they are constrained to move longitudinally.

In FIG. 4, a portion of a printing member 59, similar to the printing member and having a print bar 60, is shown. The printing member 59 has a fixed bar 62 which may be of substantially the same shape as the print bar 60. The fixed bar 62 may be shorter than the print bar 60 in a longitudinal direction and/or somewhat wider, if desired. A plurality of legs 64 extend laterally between the print bar 60 and the fixed bar 62. These legs 64 may be inclined at a predetermined angle with respect to the bars 62 and 64. The opposite internal acute angles between the legs 64, the print bar 60, and the fixed bar 62 are about 45. The legs 64 and bars 60 and 62 may be integral with each other and formed from the same sheet of metal. The legs 64 and the bars 60 and 62 form parallelograms. The portions of the legs at their junctures with the bars are necked inwardly (i.e., reduced in width) to impart greater flexibility to the legs. A print head including the bar and leg structure shown in FIG. 4 may be made similarly to the print head shown in FIGS. 2 and 3 by assembling a plurality of bar and leg units in stacked relationship separated by nonadhering spacers. Clamping bars may be disposed on opposite sides of the outermost fixed bars of the stack. An actuating mechanism may be connected to one end of each of the print bars 60 for applying longitudinal forces thereto. When such forces are applied, the legs 64 flex at their neck portions. The print bars and legs move like the links of a parallelogram linkage so that the print bars swing downwardly and impact a document for printing thereon.

Another electromechanical actuator for a print bar 66, similar either to the print bar 36 or the print bar 60, is shown in FIG. 6. A pair of counter-rotating drums 68 and 70 are disposed adjacent opposite ends of the bar 66. The drums 68 and 70 may be rotated by separate constant speed motors (not shown). The ends of the bars are wrapped approximately 180 around their adjacent drums 68 and 70. Blocks 72 of soft (nonpermanently magnetizable) magnetic material, such as iron, are secured at the terminations of each of the ends of the print bar 66. Normally, the ends of the bar 66 which are wrapped around the drums 68 and 7.0 are not in contact therewith, since these ends tend to spring away from their respective drums. Shoes (not shown) spaced from the drum may be used to prevent the ends of the bars, which are wrapped around the drums, from springing too far away from the surfaces of the drums. Fixed electromagnets 74 and 76 are disposed adjacent to the blocks 72. These electromagnets have cores 78 which are magnetized when the coils 79 of the electromagnets are energized. When magnetized, the cores attract their adjacent blocks 72. The cores 78 also act as fixed stops.

When current is applied, say, to the electromagnets 74, its core 78 is magnetized. The block 72 adjacent the magnetized core 78 is attracted thereto. The wrapped end of the print bar 66 is then pulled into frictional driving engagement with the drum 68. The torque of the drum is translated into a longitudinal actuating force (toward the right in FIG. 6) on the print bar 66. The print bar 66 is moved by this force and impacts a document for printing thereon (see FIG. 2). The electromagnet 74 develops a relatively small force which con- 6 trols a relatively large printing force applied to the print bar 66 by the drum 68.

When the block 72 strikes the core 78, the travel of the print bar 66 is arrested. Further rotation of the drum 68 then throws the end of the bar 66, which is wrapped around the drum 68, outwardly from the surface thereof. The frictional driving engagement of the wrapped end of the bar 66 and the drum 68 is thereby ended. The current which energizes the electromagnet 74 may be a pulse. The electromagnet releases at the end of the pulse and the bar 66 moves, under internally developed forces, out of printing engagement with a document. The print bar 66 may be positively returned to its initial position by passing current through the coil 79 of the other electromagnet 76 which operates like the electromagnet 74 to attract its associated block 72 and apply a temporary driving force to the print bar 66 in the opposite direction.

While electromagnets 74 and 76 are shown in FIG. 6, the armatures of solenoids may be directly connected to the wrapped ends of the bands. These solenoids desirably have built-in stops which prevent their armatures from traveling more than a fixed distance. Accordingly, intermittent driving forces may be applied from the drums 68 and 70 to the bands, as was discussed above. Instead of wrapping the free ends of the bar 66 around the drums, flexible members (for example, rubber belts) may be attached to the ends of the print bar and then wrapped around the drums 68 and 70.

An arrangement for locating a plurality of electromagnetic actuating mechanisms, including drums 68 and 70 and electromagnets 74 and 76, is shown in FIG. 7. Some of the print bars 66 are made longer than the others to provide room for the actuating mechanisms which are longitudinally offset from each other.

Another embodiment of a print head in accordance with the invention is shown in FIG. 8. Here, a plurality of printing members, each having a print bar 80, and a fixed bar 82, are provided. A plurality of arms 84 extend laterally between the respective fixed bars 82 and their associated print bars and are hinged to these bars. Pivots 86 may be used to hinge the legs 84 to the fixed bars 82. Socket joints 88 in the print bars 80 may be used to pivotally interconnect the arms 84 and the print bars 80. Corresponding fixed bars 82 and print bars 80' and their interconnecting legs define parallelograms. Accord ingly, by applying longitudinal forces to the bars, they may move similarly to the bars 36 (FIG. 2) longitudinally and laterally into printing relationship with the drum.

Printing forces are applied by actuators 90, each associated with a different one of the group of legs 84 which connect corresponding print bars 80 and fixed bars 82. These actuators include electromagnets 92 and permanent magnets 94. Extensions 96 of one of the legs of each of the group of legs 84 may be made of (or may have attached thereto a body of) soft magnetic material, such as iron. The permanent magnets 94 attract these extensions 96 and hold the print bars 80 in initial positions out of contact with the documents. When an electromagnet 92 of a selected one of the actuators is energized, as by a current pulse, the extensions 96 are attracted to the energized electromagnet 92. The legs 84 then pivot in a counterclockwise direction. The print bars 80 thereupon move longitudinally and laterally toward the document and into printing relationship therewith.

From the foregoing description, it will be apparent that there has been provided improved printing apparatus which is positive in operation and relatively low in cost. While a number of embodiments of printing apparatus in accordance with the invention have been described, variations in these embodiments, as well as other forms of apparatus embodying the present invention will undoubtedly become apparent to those skilled in the art to which the invention pertains. For example, a helix rib on acylinder may be used as a backing member instead of the herein described arbor, anvil and belt, although the latter elements are preferred, since the signals to difierent actuators must then be progressively delayed to form vertical columns of dots. Other, similar variations within the spirit of this invention are also possible. Accordingly, the foregoing description should be taken merely as illustrative and not in any limiting sense.

What is claimed is:

1. A system for printing on a line of a document which comprises:

(a) means for transporting said document along a path transverse to said line,

(b) a plurality of printing members on one side of said path each including an elongated print bar having a longitudinal printing edge substantially parallel to said line and extending the length thereof,

(c) a movable anvil member disposed opposite the printing edges on the other side of said path,

((1) means translating said anvil member in a direction longitudinally of said printing edges,

(e) fixed supporting means,

(if) said printing members also including pluralities of laterally extending legs, oblique to said printing edges, independently connecting said fixed member and the respective said print bars and defining separate parallelogram linkages, each linkage including a different one of said print bars, and

(g) actuating means for applying forces to said parallelogram linkages for changing the inclination between said legs and bars so that said bars move generally longitudinally and toward said anvil member into printing engagement with a document along said path.

2. A system for printing on a line of a document comprising:

(a) means for transporting said document along a path transverse to said line,

(b) a print head and backing means disposed adjacent each other along said line on opposite sides of said path,

() said print head comprising fixed support means, a plurality of print bars substantially parallel to said line and extending the length thereof and pluralities of legs, each of said pluralities of legs pivotal ly attaching a diflerent one of said bars to said support means and providing parallelogram linkages with said bars,

((1) said backing means comprising a backing member having a surface paralleling said print bars, a wedge-shaped anvil, and an endless belt around said backing member for translating said anvil in a direction parallel to said surface and longitudinally of said print bars, and

(e) means for selectively applying forces for urging one or more of said bars in a longitudinal direction and pivoting their said legs whereby said bars are caused to engage a document along said path and to press said document against said anvil.

3. In a printing machine for printing a line of characters on a document by an impression against the document surface, the combination comprising (a) a plurality of printing members, each of said members including:

(1) an elongated print bar extending the length of said line and having a longitudinal edge to be impressed against said surface, said bar being a thin plate of metal,

(2) a plurality of flexible legs for supporting said print bar, said legs being parallel to each other, inclined at an acute angle to said print bar and integral with said print bar at one end of said legs, said legs being thin plates of metal in the same plane as said print bar,

(b) support means for supporting said legs of said printing members with their said print bars disposed in side-by-side relationship, and

(0) means for selectively applying forces to one or more of said print bars to thereby cause their said legs to flex and thus enable movement of said bars in a direction to impress the respective longitudinal edges against said document surface.

4. A system for actuating a printing device including a plurality of print bars, fixed supporting means therefor, and separate pluralities of legs laterally extending between dilferent ones of said print bars and said fixed supporting means for supporting said print bars for longitudinal and lateral movement toward and away from a document to be printed, said bars and legs defining parallelograms, said system comprising:

(a) band members extending longitudinally from the opposite ends of said print bars,

(b) pairs of counterrotatable drums, the drums of each pair being adjacent the opposite ends of different ones of said print bars, said band members being separately, loosely disposed around ditferent ones of said drums,

(c) means for separately urging said band members into driving engagement with their associated drums, and

(d) electromagnets attached to the free end of said bands for urging said bands intodriving engagement with said drums and engageable with said free end after said free ends travel a predetermined distance related to the lateral movement of said print bars for automatically releasing said driving engagement.

5. In a system for printing a line of characters, the

combination comprising:

(a) a plurality of elongated print bars each extending along the length of said line,

(b) pairs of counter rotatable drums, one pair of each print bar, each drum of a :pair being located near a different opposite end of its associated print bar,

(0) separate band members extending longitudinally from each end of each print and being separately, loosely around associated one of said drums,

(d) means for separately urging said band members into driving engagement with their associated drums, and

(e) means for releasing said band members from said driving engagement after band members travel a predetermined distance around their associated drums.

6. The combination as claimed in claim 5, wherein said releasing means comprises stop members adjacent the ctree ends of .said band members and located to engage said free ends after said band members travel a predetermined distance.

References Cited UNITED STATES PATENTS 2,656,240 10/1953 Hell 197-1 XR 2,659,652 11/ 1953 Thompson.

2,790,697 4/1957 Wo'ckenfuse 197-1 XR 2,909,996 10/ 1959 Fitch.

2,976,801 3/1961 Dirk.

2,990,767 7/1961 Demar et al.

3,144,821 8/1964 Drejza.

3,145,756 11/1964 Kicuchi 34678 3,223,029 12/1965 Simshauser 34678 XR EDGAR S. BURR, Primary Examiner.

US. Cl. X.R. 101-93 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,444,975 Dated May 20. 1969 Inventor) E.D. Simshauser It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 39, "as" should read a 1 Column 1, line 45, "ar" should read are Column 8, Claim 5, line 42, after "print" insert bar Column 8, Claim 5, line 43, after "loosely" insert ---disposed Column 8, Claim 5, line 43, "one" should read ones SIGNED KND SEALED JUN301970 A offiw mm: E. 5am, JR. Hung Gomissioner of Patents 

1. A SYSTEM FOR PRINTING ON A LINE OF A DOCUMENT WHICH COMPRISES: (A) MEANS FOR TRANSPORTING SAID DOCUMENT ALONG A PATH TRANSVERSE TO SAID LINE, (B) A PLURALITY OF PRINTING MEMBERS ON ONE SIDE OF SAID PATH EACH INCLUDING AN ELONGATED PRINT BAR HAVING A LONGITUDINAL PRINTING EDGE SUBSTANTIALLY PARALLEL TO SAID LINE AND EXTENDING THE LENGTH THEREOF, (C) A MOVABLE ANVIL MEMBER DISPOSED OPPOSITE THE PRINTING EDGES ON THE OTHER SIDE OF SAID PATH, (D) MEANS TRANSLATING SAID ANVIL MEMBER IN A DIRECTION LONGITUDINALLY OF SAID PRINTING EDGES, (E) FIXED SUPPORTING MEANS, (F) SAID PRINTING MEMBERS ALSO INCLUDING PLURALITIES OF LATERALLY EXTENDING LEGS, OBLIQUE TO SAID PRINTING EDGES, INDEPENDENTLY CONNECTING SAID FIXED MEMBER AND THE RESPECTIVE SAID PRINT BARS AND DEFINING SEPARATE PARALLELOGRAM LINKAGES, EACH LINKAGE INCLUDING A DIFFERENT ONE OF SAID PRINT BARS, AND (G) ACTUATING MEANS FOR APPLYING FORCES TO SAID PARALLELOGRAM LINKAGES FOR CHANGING THE INCLINATION BETWEEN SAID LEGS AND BARS SO THAT SAID BARS MOVE GENERALLY LONGITUDINALLY AND TOWARD SAID ANVIL MEMBER INTO PRINTING ENGAGEMENT WITH A DOCUMENT ALONG SAID PATH. 